Narrowband and broadband communications systems are typically used by public safety agencies, for example, emergency first responder organizations, such as police or fire departments, or public works organizations. Examples of narrowband systems include a Land Mobile Radio (LMR) system or a Terrestrial Trunked Radio (TETRA) system. An example of a broadband system is one that operates in accordance with the Long Term Evolution (LTE) signaling standard. Users on narrowband and broadband systems may communicate via mobile or portable user terminals, such as portable narrowband two-way radios, mobile radios, dispatch consoles, laptops, tablets, personal digital assistants (PDA), smart phones, or other similar broadband mobile devices that communicate with one another via wired and/or wireless networks.
Regardless of the type of communication network being used, it is important to determine when system anomalies occur on a network infrastructure. One current method for determining when a service anomaly occurs on a specific network infrastructure is to set a static/predetermined threshold for each parameter that is being evaluated and to compare that predetermined threshold against statistical values retrieved for that parameter. If a retrieved statistical value is beyond (for example, greater than or less than) the predetermined threshold associated with a parameter, an alarm is typically raised to indicate a potential service anomaly. Consider an example where a statistical value associated with a percentage of dropped calls is reported for each sector in each cell site in a communication system. The reported percentage from each cell site or each sector is compared against a predetermined threshold set for the percentage of dropped calls. If, for example, the predetermined threshold for the percentage of dropped calls is set at ten percent, when any cell site or sector reports a percentage of dropped calls greater than ten percent, the system may determine that an anomaly has occurred at that cell site or sector and an alarm may be raised to indicate the anomaly.
The problem with this approach is it is difficult to set one system wide threshold for a given parameter because use of a network component may vary. For example, some cell sites may be in urban areas with high density and other cell sites may be in rural areas with larger coverage areas. It may therefore be considered “normal” for those cell sites with larger coverage areas to have a larger percentage of dropped calls than those cell sites with smaller coverage areas. Therefore, when a single threshold is set for the entire system, there may be a high number of false alarms in cell sites with a normally large percentage of dropped calls. One way to overcome generating a high number of false alarms is to set the predetermined threshold for each parameter to a value associated with catastrophe. In other words, the threshold may be set to a value that is high so that no alarms will be issued unless a catastrophe occurs. This approach clearly leads to a situation where performance degradation not rising to a catastrophic level will likely go unnoticed.
As an alternative, a predetermined threshold value may be set for each network component being evaluated. For example, a separate predetermined threshold may be set of each parameter associated with each cell site and also for given time periods, for example, a busy hour such as 9:00 am-10:00 am on a weekday versus a non-busy hour such as the same period on the weekend. Setting a separate predetermined threshold value for each network component exponentially increases the number of thresholds that have to be managed. Maintaining large numbers of predetermined thresholds is problematic because as communications systems expand with additional infrastructure, users, and/or services, the static thresholds are likely to become obsolete and must be updated to account for the dynamic changes in a communication system. In addition, there is no clear avenue for determining a value that is to be assigned to each predetermined threshold.
Accordingly, there is a need for an apparatus and method for determining context aware and adaptive thresholds in a communications system.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.